1. Field of the Invention
This invention relates to a synthetic resin molded surface fastener having a multiplicity of engaging elements on an engaging surface of a substrate sheet and a method of manufacturing the molded surface fastener, and more particularly to a molded surface fastener having an ornamental pattern formed on its front or front and rear surfaces simultaneously with the molding and a method of and an apparatus for manufacturing the molded surface fastener.
2. Description of the Related Art
In manufacturing woven and knit fiber surface fasteners to be used as opening and closing means for garments, bags, etc. as well as detachably attaching means such as fastening bands, various attempts have been made to improve the fashionability of products using surface fasteners. To this end, it has been a common practice to form an ornamental pattern, such as characters, design, symbol, etc. on the surface fastener's engaging surface, from which a multiplicity of hooks or loops as engaging elements stand, in an effort to give the surface fastener a good external view.
For example, according to Japanese Patent Publication No. Hei 3-79001, an ornamental pattern, such as characters, design, symbol, etc., is formed on the engaging surface of a surface fastener by press-heating and solidifying soft and flexible material, such as silicone rubber, onto the engaging surface, on which a multiplicity of engaging elements in the form of hooks or loops stand, of the surface fastener.
Further, according to Japanese Patent Laid-Open Publication No. Sho 62-19105, a desired pattern, such as desired characters, design, symbol, etc., of dye paste is stamped on the rear surface, which is opposite to the engaging surface, of a surface fastener and sucking the dye paste on the rear surface to the engaging surface by a vacuum pump disposed on the side of the engaging surface of the surface fastener. Then the resulting surface fastener is treated with a dyeing process so that characters, design, symbol, etc. come out on the engaging surface of the surface fastener.
Japanese Patent Laid-Open Publication No. Hei 3-69658 discloses a method of and an apparatus for dyeing a surface fastener. According to this disclosure, a desired pattern, such as characters, design, symbol, etc., is formed by spouting ink drops over the engaging surface of a surface fastener in a dot-matrix format, based on the data regarding the position and shape of the pattern, by ink-jet means and then sucking ink on the engaging elements from the side of the rear surface so that the ink reaches the substrate sheet. Then the substrate sheet and the engaging elements are dyed so that a pattern of characters, design, symbol, etc. come out definitely.
In the meantime, recent advances of surface fasteners entirely molded of synthetic resin by injection molding are astonishing; as a result, in addition to molded surface fasteners having a certain degree of rigidness to be used as conventional industrial materials and interior ornamental goods, various molded surface fasteners having a very high degree of flexibility have been developed. Application of this flexible molded surface fasteners are on the increase for ordinary garments and daily goods strongly requiring high flexibility from a fashionability view point.
Nevertheless, all of the above-mentioned methods of forming an ornamental pattern are aimed at fiber surface fasteners. Practically, it is virtually impossible to adopt these methods in molded surface fasteners made by such as integral injection molding for the following reasons. Any effective ornamental pattern forming method for molded surface fasteners has not been established yet.
Although the method disclosed in Japanese Patent Publication No. Hei 3-79001 could be applied to the above-mentioned molded surface fastener, an ornamental pattern area would have bulged from the engaging surface of the surface fastener so that the engaging elements around the bulged ornamental pattern area would tend to fail to catch the engaging elements of a companion surface fastener when the two surface fasteners are pressed to engage, thus it is probable that a desired engaging strength required in the surface fastener can not be achieved.
Assuming that the methods disclosed in Japanese Patent Laid-Open Publications Nos. Sho 62-19105 and Hei 3-69658 could be applied to the molded surface fastener, since the substrate sheet of the integrally molded surface fastener is a molded sheet of synthetic resin, it would have been impossible to absorb dye liquid or ink through the molded substrate sheet unlike the woven or knit fiber substrate sheet having minute gaps.